Sprouty2 mediated tuning of signalling is essential for somite myogenesis

Background: Negative regulators of signal transduction cascades play critical roles in controlling different aspects of normal embryonic development. Sprouty2 (Spry2) negatively regulates receptor tyrosine kinases (RTK) and FGF signalling and is important in differentiation, cell migration and proliferation. In vertebrate embryos, Spry2 is expressed in paraxial mesoderm and in forming somites. Expression is maintained in the myotome until late stages of somite differentiation. However, its role and mode of action during somite myogenesis is still unclear. Results: Here, we analysed chick Spry2 expression and showed that it overlaps with that of myogenic regulatory factors MyoD and Mgn. Targeted mis-expression of Spry2 led to inhibition of myogenesis, whilst its C-terminal domain led to an increased number of myogenic cells by stimulating cell proliferation. Conclusions: Spry2 is expressed in somite myotomes and its expression overlaps with myogenic regulatory factors. Overexpression and dominant-negative interference showed that Spry2 plays a crucial role in regulating chick myogenesis by fine tuning of FGF signaling through a negative feedback loop. We also propose that mir-23, mir-27 and mir-128 could be part of the negative feedback loop mechanism. Our analysis is the first to shed some light on in vivo Spry2 function during chick somite myogenesis

Profil des systèmes alimentaires - Burkina Faso. Activer la transformation durable et inclusive de nos systèmes alimentaires

Cette note est issue d'une collaboration entre le Ministère de l'Agriculture, l'Union Européenne, la FAO et le Cirad. Elle s'inscrit dans l'initiative Catalyser la transformation durable et inclusive des systèmes alimentaires. La méthode d'analyse combine des données quantitatives, une approche participative impliquant les acteurs publics et privés liés aux systèmes alimentaires, et une analyse qualitative. Un atelier de lancement (05/11/2020) a permis de circonscrire l'analyse et d'identifier les enjeux majeurs à approfondir. Un travail de revue de la bibliographie et des données disponibles, ainsi que des entretiens approfondis auprès de personnes ressource, ont permis d'approfondir les processus à l'oeuvre et d'affiner la compréhension systémique. Le découpage en systèmes alimentaires territoriaux a été réalisé sur la base de la compilation d'une série de cartes thématiques, portant sur les activités, les impacts et les principaux moteurs du système alimentaire. Enfin, un atelier de synthèse (02/02/2021) a permis de partager et d'affiner les résultats et d'identifier les principaux leviers à actionner pour améliorer la durabilité du système

Sprouty2 and Spred1-2 Proteins Inhibit the Activation of the ERK Pathway Elicited by Cyclopentenone Prostanoids

Sprouty and Spred proteins have been widely implicated in the negative regulation of the fibroblast growth factor receptor-extracellular regulated kinase (ERK) pathway. In considering the functional role of these proteins, we explored their effects on ERK activation induced by cyclopentenone prostanoids, which bind to and activate Ras proteins. We therefore found that ectopic overexpression in HeLa cells of human Sprouty2, or human Spred1 or 2, inhibits ERK1/2 and Elk-1 activation triggered by the cyclopentenone prostanoids PGA1 and 15d-PGJ2. Furthermore, we found that in HT cells that do not express Sprouty2 due to hypermethylation of its gene-promoter, PGA1-provoked ERK activation was more intense and sustained compared to other hematopoietic cell lines with unaltered Sprouty2 expression. Cyclopentenone prostanoids did not induce Sprouty2 tyrosine phosphorylation, in agreement with its incapability to activate tyrosine-kinase receptors. However, Sprouty2 Y55F, which acts as a defective mutant upon tyrosine-kinase receptor stimulation, did not inhibit cyclopentenone prostanoids-elicited ERK pathway activation. In addition, Sprouty2 did not affect the Ras-GTP levels promoted by cyclopentenone prostanoids. These results unveil both common and differential features in the activation of Ras-dependent pathways by cyclopentenone prostanoids and growth factors. Moreover, they provide the first evidence that Sprouty and Spred proteins are negative regulators of the ERK/Elk-1 pathway activation induced not only by growth-factors, but also by reactive lipidic mediators

The Causal Impact of Fear of Unemployment on Psychological Health

We analyze the effect of job insecurity on psychological health. We extend the group of people being affected to employees who have insecure jobs to account for a broader measure of the mental health consequences of potential unemployment. Using panel data with staff reductions in the company as an exogenous source of job insecurity, we find that an increase in fear of unemployment substantially decreases the mental health status of employees. Quantile regression results yield particularly strong effects for individuals of already poor mental health.Das vorliegende Papier untersucht den Effekt von Arbeitsplatzunsicherheit auf die psychische Gesundheit. Im Gegensatz zu früheren Untersuchungen wird dabei nicht nur tatsächlicher Arbeitsplatzverlust betrachtet, sondern der Effekt subjektiver Arbeitsplatzunsicherheit ins Zentrum der Analyse gerückt. Damit wird ein breiteres Spektrum möglicher Effekte von Arbeitsplatzunsicherheit auf die mentale Gesundheit beleuchtet. Die empirische Analyse von Paneldaten aus Deutschland, die unternehmensspezifischen Arbeitsplatzabbau als exogene Determinante subjektiver Arbeitsplatzunsicherheit nutzt, zeigt dass vermehrte Furcht vor Arbeitsplatz eine deutlich verschlechterte psychischen Gesundheit nach sich zieht. Die Ergebnisse von Quantilsregressionen deuten zudem darauf hin, dass sich Jobangst in besonderem Maße negativ auf Arbeitnehmer auswirkt, deren mentaler Gesundheitszustand bereits angegriffen ist